Document copy authentication

(19)

(11)

EP 0 547 837 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	13.07.1994 Bulletin 1994/28

(43)	Date of publication A2:
	23.06.1993 Bulletin 1993/25

(21)	Application number: 92311289.0

(22)	Date of filing: 10.12.1992

(51)	International Patent Classification (IPC)⁵: H04L 9/32

(84)	Designated Contracting States:
	DE FR GB

(30)

Priority:

19.12.1991 US 810644

(71)	Applicant: XEROX CORPORATION
	Rochester New York 14644 (US)

(72)	Inventors:
	Merkle, Ralph C. Sunnyvale, California 94087 (US) Bloomberg, Dan S. Palo Alto, California 94306 (US) Brown, John S. San Francisco, California 94115 (US)

(74)	Representative: Johnson, Reginald George et al
	Rank Xerox Ltd Patent Department Parkway Marlow Buckinghamshire SL7 1YL Marlow Buckinghamshire SL7 1YL (GB)

(56)

References cited: :

(54)	Document copy authentication

(57) A system for authenticating a hard copy of an original document (20). The system employs a special copying machine (25) at the sender's end together with a special ID card (smart card (30)) or other user identification for activating the special machine (25), and a special copying machine at the receiving end. At the sender's station, the original document and ID card are inserted into the machine (25). The latter digitizes the document text, to produce a digital signature which incorporates unique information from the sender's ID card. This machine (25) then produces a hard copy (35) of the document to which is added the digital signature (36). The sender retains the original, but forwards the copy to the recipient or receiver.
The receiver then inserts the received copy into the machine (25) at his location, which digitizes and processes the document text and signature and indicates whether the digital signature is valid. Preferably a dual key authentication system is used, with the digital signature incorporating the sender's secret signing key, and the receiver using the related public key in the validation process.

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